Residents of Paradise bitterly complained in the wake of the Camp Fire that Butte County’s early warning system failed them, and now a detailed Bay Area News Group analysis shows just how thorough that failure was.

The review revealed that thousands of critical cellphone messages were missed, delayed or lost — a disturbing reminder of the fragility of our electronic notifications systems, even as more of our lives move online.

“The system failed. Technology, the thing I trust most, failed,” said Lisa Parr, an accountant who had signed up to get the county’s emergency alerts but never received one. Hard at work on her computer and phone that fateful morning, she was unaware of approaching flames and escaped with just moments to spare. “The system that was supposed to help save us — it didn’t.”

This news organization’s review found problems at every level — many residents didn’t sign up for the system, officials didn’t trigger warnings for every neighborhood, and overloaded or damaged cellular networks often failed to deliver warnings to the intended recipient. Meanwhile, flames engulfed the region with stunning speed, leaving little room for error.

A Butte County spokeswoman said Sheriff Kory Honea will conduct an analysis and issue a report when time allows.

“I wish we had opportunity to get more alerts out, more warning out,” said Honea during a community meeting on the third day of the fire. “We try to use as many systems as we can. … But in the heat of this, it was moving so fast, it was difficult to get that information out.”

To better understand how the failures occurred, this news organization requested evacuation alert records from the Paradise and Chico police departments and from Butte County, as well as cell tower information from the California Public Utilities Commission.

A review of alerts issued by the county and Paradise police in the hours after the fire started on Nov. 8 shows that no evacuation orders were issued by the county to one six-square-mile swath of the city. Another four-mile stretch of town received merely a warning; the actual order to flee came 7.5 hours later, long after homes were reduced to ashes.

Prior to the Camp Fire, only an estimated one-quarter of the region’s residents had signed up to get emergency messages — but even when they signed up, many calls didn’t reach them. Success varied from geographical zone to zone, generally deteriorating as the fire spread and the infrastructure was damaged or overwhelmed. Even in the best-performing zones, 25 percent of alerts did not make a connection to the resident’s phone. In the worst zone, the call failure rate was 94 percent.

Seventeen cell towers burned that first day, according to records obtained from the CPUC. During the first two weeks of the fire, a total of 66 cell phone towers were damaged or out of service, causing phones to go silent or calls to be dropped as surviving towers became overloaded by traffic.

“We really need to get better at this,” said disaster expert Kelly McKinney, author of the book Moment of Truth: The Nature of Catastrophes and How to Prepare for Them. McKinney urges the creation of a state system to provide a notification template and backup help for local responders.

“The public needs to understand what to expect — what will happen, when it will happen and who is accountable for making it happen,” said McKinney, who is senior director of emergency management at the medical center NYU Langone Health and former deputy commissioner at New York City’s Office of Emergency Management. “If you don’t have those three things, it is wishful thinking. And wishful thinking always fails you in a disaster.”

Paradise and its surrounding communities — where 86 people perished in the fire — is not the only place where planning has not been up to the task. In other California disasters, alerts and evacuations have fallen short, including the 2017 flooding of downtown San Jose and Tubbs Fire of Sonoma County, which killed 22. In last January’s mudslides in Montecito, a message was issued while hillsides already were collapsing, killing more than 20 people.

In the San Francisco Bay Area, the public warning systems are a patchwork of technologies, personnel, media, vendors and policies, and there are both duplications and gaps in their coverage, according to a 2017 report by Bay Area Urban Areas Security Initiative, a federally-funded project to improve the region’s capacity to respond to catastrophic events. As a result, the messages people receive in one city are often different than those in another.

“California’s alert system is, in reality, 58 county alert systems duct-taped together, with 58 different processes and capabilities,” McKinney said. “If we’re going to remove the duct tape and bolt and wire it together, so it’s all one machine, the state has to do it.”

California counties’ individual warning systems sprang up ad-hoc to address various threats. While there’s been a trend toward integrating systems at the federal level, local systems are still fragmented, driven by competitive marketing among commercial vendors. Almost all of our warning tools must be activated one-by-one and do not support simultaneous activation using a tool called Common Alerting Protocol. The protocol, adopted by the federal government, allows warning messages to be sent all at once across many platforms.

This creates otherwise avoidable delay, additional workload, and opportunities for error for warning originators, according to the report. And there are few explanations of different warning methods, what those methods mean, and what steps should be taken when a warning is issued.

New state laws aim to improve notification in the future. One mandates statewide guidelines and training programs for local governments. Another authorizes counties to automatically enroll residents into emergency notification systems, gaining access to phone numbers through utility bills and other services.

In Paradise, only residents who had registered for CodeRED, the county’s alert system, had any chance of knowing what was happening during the Camp Fire. County logs from Nov. 8 show that messages reached 16,683 phones but failed to reach another 10,869 despite repeated attempts. Paradise Police reached a total of 4,855 phones but did not reach 4,099. Combined, authorities also sent more than 6,000 texts and 6,700 emails that first day, with additional alerts issued in the days following. An estimated 38,702 people lived in the towns of Paradise, Magalia and Concow, with others scattered in more rural parts of the county.

Butte County used a commercial system similar to those used in most Bay Area counties, connecting to landlines, cell phones, emails and social media.

There is a second type of alert system, also available to Bay Area counties, where notifications such as Amber Alerts can be sent to cell phones regardless of whether residents have opted-in. This system, the Federal Emergency Management Agency’s Wireless Emergency Alert (WEA), blankets an area with a warning.

But WEA’s geographical targeting, based on a labyrinth of cell towers and a honeycomb of tower signal “sectors,” is not terribly precise. Any WEA alert will likely overshoot or undershoot the desired alert area.

Both systems are vulnerable. They rely on local officials, who are inevitably overwhelmed in the early hours of a catastrophe, scrambling to save lives and get resources to the danger, according to McKinney. As the fire consumed Paradise, thousands of calls poured in to 911 — where only two dispatchers were working.

In Paradise, officials issued evacuation alerts for 10 different zones in the city in just one hour, between 7:47 a.m. and 8:43 a.m. But alerts were not sent in four other zones, equally at risk. The Butte County Sheriff’s office, which issued the alerts throughout the county, referred questions about the four zones to Paradise Police, who did not respond to a request for comment.

“It’ll never be perfect, when there’s limited time,” said Daniel Gonzales of the RAND Homeland Security and Defense Center, who led a 2016 study about warnings for the U.S. Department of Homeland Security. But with review and more pre-planning and practice, “it should be possible to do much better than what happened in Paradise … to minimize errors that might happen during a very stressful set of conditions.”

To improve matters, officials will have to solve one weakness of any electronic alert system: its dependence on electricity.

Even during a power outage, messages that are sent to a landline have a better chance of landing. That’s because power is sent to the phones through copper wires, which are more heat-resistant. Phone company offices have extensive battery systems, as well as backup generators, according to Santa Clara University School of Law professor and former CPUC commissioner Catherine Sandoval.

But cell phone coverage is less reliable. Cell towers need electricity to operate, but there is no requirement to have backup electrical power at cell towers. Also, cell service relies on fragile glass fiber optic networks to route calls from the base stations to switching stations, then to customers. And because the systems are designed in a straight line, when one tower goes down, incoming calls reverse direction and bounce back.

Rural areas are especially vulnerable, with more limited networks, said RAND’s Gonzales. And emergency officials are not told which towers are down or which carriers have lost service.

“The current technology gives us ubiquity, but not great resiliency,” said Jamie Barnett, former chief of the Public Safety & Homeland Security Bureau of the Federal Communications Commission.

“Cellular networks allow us to have voice and data communications nearly everywhere now,” he said. “But cell phones are really just little radios, and they are dependent on the viability of the cell tower and the viability of the ‘backhaul’ into the network.”

In the eastern Paradise neighborhoods first hit by fire, about 56 percent of the 4,272 emergency alert calls failed due to what CodeRED manufacturer OnSolve calls “operator intercept” or “timed out,” meaning that the phone has been disconnected, the number changed or no longer in service, or — most likely — the network didn’t find sufficient signal strength or bandwidth to make the call work, due to cell tower failure.

By 1:30 a.m. next morning, evacuation orders were nearly futile for residents of the old logging town of Stirling City and other rural communities up on Paradise Ridge, north of Paradise.Records show that a stunning 98 percent of the phone calls made to that area to evacuate never reached a person.

“This has been a growing issue with emergency communications — fostered by transition to more and more people using cell phones and other systems that are reliant on fiber,” said Sandoval. “That’s the problem with big fires: The infrastructure burns. As you lose both power and telephones, that creates failure.

“What you end up with is a situation that takes us back to the 1940s,” she said, “where heroic responders drive up and down streets, taking their lives into their hands, using bullhorns.”

Lisa M. Krieger is a science writer at The Mercury News, covering research, scientific policy and environmental news from Stanford University, the University of California, NASA-Ames, U.S. Geological Survey and other Bay Area-based research facilities. Lisa also contributes to the Videography team. She graduated from Duke University with a degree in biology. Outside of work, she enjoys photography, backpacking, swimming and bird-watching.